I think there is something that is being forgotten here. Corel are
shipping several things, but presumably they are only dynamically
linked. So the reason why they need a licence exemption isn't that
their frontend is derivative of lib-apt, but rather that the copyright
on lib-apt would require the `whole work' - ie, all the things which
are bound together at runtime - to be licensed under the GPL.
However, of course, lib-apt isn't the only thing that is bound
together at run-time with Qt in this program. dpkg is too - the fact
that the interface is program call rather than dynamic linking is an
irrelevant technical detail. (This case seems similar to the one
where Next wanted to ship GCC with their own Objective-C frontend, but
not to release the frontend under the GPL. RMS had his laweyrs write
to them and Next changed their mind.)
I'm unlikely to be happy to make a licence exemption for Qt, as I have
stated on numerous previous occasions. Can someone please send me
contact details for someone relevant at Corel, so I can talk to them
about it ? I'll try to be nice to them :-).
Ian.